Are the iPhone and iPad touchscreen interfaces usable and accessible enough?

Today marks the launch of the iPad in Australia. As an Apple touch-screen device, it uses very similar software to the iPhone, which has been widely praised both for its ease-of-use with the general population, and its accessibility features for people with disabilities. But is it usable enough and accessible enough?

Some of the accessibility features of the iPhone and iPad include a high-contrast visual mode and zoom for people with low vision, and read-aloud for on-screen options. These are great features that certainly enhance the accessibility and usability of the iPhone and iPad for some people, but some people are now arguing that they don't go far enough.

A recent article on DiVine (opens in new window) highlights the issues that face some people with disabilities, including the inability of people to use alternative pointing devices, and the lack of physical buttons. Users who need to use a mouse, joystick or alternative device will have a lot of trouble with a device that requires careful movement of fingers.

Even for people without a disability, there are often problems with using touch-screen interfaces. For example, when using a real keyboard or a real button, it's possible to feel with your fingers when a key or button has been pressed. This is known as haptic feedback. With on-screen buttons as in a touchscreen device, this haptic feedback is absent, and users have to look at the screen (or listen) to know that something has been successfully pressed.

The move for new technology to embrace accessibility for people with disabilities is a process the industry has been through before as home computers became common. How long will it take for the process to be complete with newer, handheld devices?